The present invention is based on a vehicle computer arrangement, particularly for a motor vehicle, a train, an airplane or ship, having at least two computers and at least one data bus, via which the at least two computers are interconnected.
Modern vehicles, particularly motor vehicles, are generally equipped with a plurality of electronic systems, i.e. an audio-signal system and a safety system, functioning independently of one another. The audio-signal system generally includes an AM/FM broadcast receiver, a compact cassette (CC) or a compact disk (CD) player, a tone controller, for example, in the form of an equalizer, an amplifier and loudspeakers. The broadcast receiver and the CC or CD player, and often the equalizer as well, are accommodated together in a common housing provided for installation in the dashboard of a motor vehicle, the housing being standardized with respect to its size, thus ensuring that the audio system can be installed in at least a majority of motor-vehicle dashboards.
The safety system mentioned generally functions completely independently of the audio system. The safety system is usually made up of a plurality of sensors distributed over the motor vehicle, and a central, application-specific, integrated circuit (ASIC) for recording the sensor signals and possibly for triggering safety-relevant functions. In addition, the safety system controls actuators, for example, for opening and closing the doors or windows, and, for instance, an alarm system.
In addition, the newest motor vehicles are also provided with a diagnostic system which monitors the functioning of the motor-vehicle engine, the power transfer, the fuel system and possibly further components. The diagnostic system can be connected to an external computer, so that the recorded diagnostic information can be read out from the computer of the diagnostic system and evaluated, e.g. for repairing a vehicle. Moreover, the diagnostic system also includes display devices, integrated into the dashboard, which inform the motor-vehicle driver about the operating state of the vehicle.
In the same way, various modern motor vehicles are provided with navigation systems which, from sensors located on the vehicle, e.g. a compass, an odometer, as well as the output signals of a GPS (Global Positioning System) receiver, determine the current vehicle position, and by comparing the current vehicle position to an electronically stored map, with the aid of a start position and destination position specified by the motor-vehicle driver, generate navigation information for guiding the motor-vehicle driver.
In addition, motor vehicles are often also equipped with communication systems, e.g. in the form of mobile telephones. Particularly well-developed systems are voice-controlled, and thus allow the motor-vehicle driver to initiate or receive telephone calls while traveling, without at the same time having to remove a hand from the steering wheel or being otherwise distracted from the traffic situation.
Each of the described systems is provided with its own special processor or ASIC for processing the special software necessary for the devices. If, at this point, a motor-vehicle owner would like to retrofit one of the described systems in his motor vehicle, he/she is forced to acquire and install a complete system, including the special processor necessary for the system, in the vehicle.
A computer system for a vehicle, particularly a motor vehicle, is known from WO 97/19833, in which the various above-described, independent components are integrated, and which is provided with an open hardware architecture and a shared operating system for the various components, thus making it possible to retrofit one of the above-indicated or further components by connection to the existing computer arrangement.
The German Patent DE 35 43 996 C2 describes a multi-computer arrangement for a vehicle, particularly a motor vehicle, in which the various computers are interconnected for the purpose of exchanging information. Different, suitably characterized, permanently stored data records are stored in write-read memories allocated to the various computers to permit, for example, the user to subsequently adapt the program flows to be processed in the computers. Using a freely programmable memory, it is possible to access the stored data records at the beginning of the computer operation by inputting corresponding identifiers, and thus to adapt the program flows for the computers.
The vehicle computer arrangement of the present invention has the advantage that the demands for system stability and safety are met, accompanied at the same time by an increase in flexibility when equipping or retrofitting a vehicle fitted with the vehicle computer arrangement with various further applications. To that end, the vehicle computer arrangement is provided with a monitoring circuit which ensures that access to safety-critical operating-program components or components of the computer arrangement is enabled only for an authorized group of people, e.g. the motor-vehicle manufacturer. Thus, the safety demands of the motor-vehicle manufacturers, who, in view of threatening warranty claims, have an interest in the integrity of the operating programs specified by them, are fulfilled. An uncontrolled access to sensitive areas of the vehicle computer arrangement or of the operating programs is therefore effectively ruled out.
Along the lines of a cost reduction, it is particularly advantageous if at least one of the computers of the vehicle computer arrangement is a standard personal computer, and a standard operating system is used for the communication between the computer(s) and further components connected to the computers. Underlying this is the consideration that standard personal computers are produced in much greater quantity than, for example, special computers tailored to specific applications such as those of a vehicle navigation system or of an engine management. Since the production costs are far less crucial for standard personal computers because of their much larger production numbers compared to special computers, a considerably lower production cost results for vehicle computer arrangements based on standard personal computers. The situation is the same with the operating systems used for the communication of the computers among themselves or with the further connected components; falling back on standard operating systems makes it possible to dispense with a time-consuming and therefore costly new development of special operating systems.
In addition, the use of standard operating systems for the computers of the vehicle computer arrangement has the advantage that a widespread and generally accepted standard for data exchange is available for further components that are subsequently connectible to the vehicle computer arrangement. Thus, the need to adapt further connectible components to various operating systems is eliminated, as well as the associated additional costs.